| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Diabetes, ischemia/reperfusion, and some drus such as cyclosporin induce renal failure. Free radicals are thought to be an important factor in renal injury but its mechanism is not clear. Cytochrome P450 (P450) which is a monooxygenase produces active oxygen species. It is reported that an inhibitor of P450 reduces renal injury caused by ischemia/reperfusion. In this study, a role of free radical produced by P450 in renal injury was investigated. First, isoforms of P450 which produced hydroxyl radicals were identified by electron spin resonance (ESR). CYP2B1 and 3A2 had the highest activity for hydroxyl radical production and CYP2E1 and 4A2 had the next highest activity. CYP2B1 and 3A2 are phenobarbital (PB)-inducible forms in rat liver. CYP2E1 is induced in live and kidney by alcohol and diabetes. CYP4A2 is a major renal P450 and induced by cyclosporin. Treatment of rats with PB induced lipid-peroxidation and increased 8-hydroxy-2'-deoxyguanosine (8-OHdG), DNA damage maker, in rat liver. In addition, immunochemical study with antibodies against CYP2B1 and 8-OHdG revealed that areas stained with CYP2B1 antibody were identical with those with 8-OHdG antibody. Furthermore, LLC-PK1 cells which derived from kidney was used for ischemia/reperfusion model. Cell damage was assayd by release of lactate dehydrogenase (LDH). An inhibitor for electron transfer system constituted with NADPH, P450-reductase, and P450 decreased the release of LDH,indicating that the inhibitor decreased the cell damage caused by active oxygen species.
These findings suggested that active oxygen species produced by P450 damaged membrane lipids and reached genomic DNA.P450 has an important role in renal injury caused by free radicals.
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